<template>
  <div class='xtx-carousel' @mouseenter="stopFn" @mouseleave="autoplayFn">
    <ul class="carousel-body">
      <li class="carousel-item" :class="{fade: imgIndex == i}" v-for="(item,i) in sliders" :key="item.id">
        <RouterLink :to="item.hrefUrl">
          <img :src="item.imgUrl" alt="">
        </RouterLink>
      </li>
    </ul>
    <a href="javascript:;" class="carousel-btn prev" @click="toggle(-1)"><i class="iconfont icon-angle-left"></i></a>
    <a href="javascript:;" class="carousel-btn next" @click="toggle(1)"><i class="iconfont icon-angle-right"></i></a>
    <div class="carousel-indicator">
      <span @click="imgIndex = i" :class="{active: imgIndex == i}" v-for="(item,i) in sliders" :key="i"></span>
    </div>
  </div>
</template>

<script lang="ts">
export default  {
  name: 'XtxCarousel'
}
</script>
<script setup lang="ts">
import { PropType, ref, watch, onUnmounted, toRefs } from 'vue'
import { sliderType } from '@/types/resultsType'
const props = defineProps({
  sliders: {
    type: Array as PropType<sliderType[]>,
    default:() => []
  },
  autoplay: {
    type: Boolean,
    default: false
  },
  duration: {
    type: Number,
    default: 3000
  }
})
const { sliders, autoplay, duration } = toRefs(props)
// 显示图片的索引
const imgIndex = ref(0)

// 自动轮播定时器
let timer: number | null  = null
// 自动轮播方法
const autoplayFn = () => {
  // 如果列表长度为0或自动轮播属性为false则跳出
  if (!sliders.value.length || !autoplay.value) return
  if (timer) clearInterval(timer as number)
  timer = window.setInterval(() => {
    imgIndex.value ++
    if (imgIndex.value >= sliders.value.length) imgIndex.value = 0
  }, duration.value)
}
// 监听轮播图和autoplay的变化
watch([() => sliders.value,() => autoplay.value],() => {
  autoplayFn()
},{ immediate:true })

// 鼠标进入停止，移出开启自动，前提条件：autoPlay为true
const stopFn = () => {
  if (timer) clearInterval(timer)
}

// 上一张下一张
const toggle = (step:number) => {
  const newIndex = imgIndex.value + step
  if (newIndex >= sliders.value.length) {
    return imgIndex.value = 0
  }
  if (newIndex < 0) {
    return imgIndex.value = sliders.value.length - 1
  }
  imgIndex.value = newIndex
}

  // 组件消耗，清理定时器
onUnmounted(() => {
  if (timer) clearInterval(timer as number)
})
</script>
<style scoped lang="less">
.xtx-carousel{
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel{
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0,0,0,0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background:  #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0,0,0,.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev{
        left: 20px;
      }
      &.next{
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
</style>
